Real-time detection mechanism with self-calibrated steps for the hardware baseline to detect the malfunction of liquid vaporization system in AMAT TEOS-based Dxz chamber

ABSTRACT

A method of preventing the scrapping of semiconductor substrates due to improper deposition of thin films in a thin film vaporization system is disclosed. This is accomplished by providing a method of self-calibrating and testing the flow of liquid precursors in the vaporization system prior to the start of the deposition process. The vaporization of the liquid precursor in the deposition chamber and the concomitant pressure change in the chamber are correlated. This correlation is then used as a real time monitoring mechanism for self-calibrating and testing the flow of liquid precursors through the vaporization system. That the pressure change due to vaporization in the chamber is used as the key parameter, the thin film deposition is hence monitored by that parameter which directly predicts the film deposition characteristics. Consequently, each thin film run is assured of a successful run.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to the manufacture of semiconductordevices, and in particular, to a real-time monitoring of vaporizationand liquid flow rate of precursor liquid components used in theformation of thin films on semiconductor substrates in an AMATTEOS-based Dxz Chamber.

(2) Description of the Related Art

It is common practice to process thin films in chambers manufactured byApplied Materials, Inc., (AMAT). These chambers provide various controlsin order to achieve stable operations such as having uniform thicknessand topography of the resultant films. As is described more in detailbelow, factors contributing to the stability of the properties of thefilms include the flow rate of the precursor liquids that are vaporizedto deposit the desired films on a substrate, as well as the continualvaporization process. It has been the experience in the presentmanufacturing line that it is difficult to detect a malfunction in thevaporization process with the AMAT TEOS-based Dxz Chamber, and,therefore, a real-time monitor mechanism has been developed which isdisclosed later in the embodiments of the present invention.

In U.S. Pat. No. 5,531,183 by Sivaramakrishnam, et al., issued toApplied Materials, Inc., a vaporization sequence is disclosed formultiple liquid precursors used in semiconductor thin film applications.This sequence is formulated in order to reduce the temperaturesensitivity of the respective liquid precursors in either the vapor orliquid state. The need for such a sequence is described because of thenature of processing thin films as follows:

Liquid source precursors or components are often used in processing thinfilms, such as, for example, silicon oxide films. These liquids aretypically stored in source tanks and a re delivered as vapors to adeposition chamber using a delivery system wherein each liquid flowsthrough a separate line and liquid flow meter (to provide individualcontrol of the flow rate of each reactant) and then is injected as avapor into a common manifold. The vapors flowing in the manifold arethen introduced into processing chamber connected to the manifolddownstream of the points of entry of the gases and vaporized liquidsource precursors into the manifold.

While the vaporous components, upon entering the processing chamber,perform satisfactorily, for example to form a thin film on asemiconductor substrate, it has been found that problems of eithercondensation of the previously vaporized liquid source component(s) orboiling of the still liquid component(s) in the delivery system canoccur, depending upon the temperatures maintained at various points inthe delivery system, including along the manifold. For example, if thetemperature at a particular point along the manifold is too low (a coldspot), condensation of a previously vaporized liquid precursor source orcomponent may occur at that point in the manifold. On the other hand,maintenance of too high a temperature in the manifold (to prevent suchundesirable condensation) can result in boiling/decomposition of aliquid component in the liquid supply line of the particular liquidcomponent upstream of its vaporization and injection into the manifold.This, in turn, can lead to instabilities in the flow rate control ofthat particular component due to fluctuations of the liquid flow meteras the boiling or near boiling component flows through it.

For example, Sivaramakrishnam, et al., describe that in the formation ofa thin film of silicon oxide on a semiconductor substrate for use as aplanarization layer, the silicon oxide is usually doped with phosphorusand/or boron to enhance the flow characteristics of the silicon oxideduring a subsequent planarization step. This results in the use of aliquid silicon source precursor, such as an alkoxysilane, e.g.,tetraethylorthosilicate (TEOS), a liquid phosphorus source precursorsuch as, for example, trimethylphosphite (TMP), triethylphosphite (TEP),or triethylphosphate (TEPO); and/or a liquid boron source precursor suchas, for example, trimethylborate (TMB) or triethylborate (TEB).

Following Sivaramakrishnam, in a vaporization system such as shown inFIG. 1, these liquids are stored in separate source tanks ((10 a), (10b), (10 c)) and are delivered as vapors to a deposition chamber using adelivery system wherein the liquid sources of silicon, phosphorus, andboron flow through separate lines ((20 a), (20 b), (20 c)), liquid flowmeters ((30 a), (30 b), (30 c)) into valves ((40 a), (40 b), (40 c)) andthen are respectively injected as vapors into a common manifold (50)where they are usually mixed with a carrier gas from its own tank (60)flowing through its own flow meter (63) and valve (65) into the commonmanifold, which in turn leads the mixture to distribution nozzle (55) inthe chamber. The vapors flowing in the manifold are then further mixedwith a vapor source of oxygen in tank (70), usually just prior to entryinto deposition chamber (80) to avoid premature reaction, to form thedoped silicon oxide film on the semiconductor substrate (90) held on aheated holding fixture (85) in the deposition chamber. Typically thereaction may be either a thermal CVD reaction or a plasma-enhanced CVDreaction. The presence of the dopants in the resulting silicon oxidefilm lowers the temperature at which the silicon oxide film may besubsequently reflowed to produce a planarized film.

While the vaporous components, such as the reactants described above,react in a deposition chamber to form a satisfactory doped silicon oxidefilm useful for planarization of a structure formed on a semiconductorsubstrate, Sivaramakrishnam, et al., report that problems of eithercondensation or boiling in the delivery system can occur. As describedabove, if the temperature at a particular point along the manifold istoo low, condensation of a previously vaporized reactant may occur atthat point in the manifold, while maintenance of too high a temperaturein the manifold can result in boiling/decomposition of a liquidprecursor in the liquid supply line of that reactant upstream of itsvaporization and injection into the manifold, resulting in erratic flowof the liquid precursor through the liquid flow meter.

The resultant instabilities in the flow rate of the reactants, due toeither problem, can interfere with the satisfactory formation of ahomogeneous product such as a properly doped silicon oxide film. Forexample, in the above described formation of a phosphorus and/orboron-doped silicon oxide film, premature condensation can effectincorporation of one or more of the dopants into the film, as well aseffecting the uniform distribution of the dopant(s) in the silicon oxidefilm. Additionally, each microlayer of the thin film of silicon oxidecould incorporate different concentrations of the respective dopants ifthe vaporization rates and flow into the processing chamber are notuniform.

It is, therefore, suggested by Sivaramakrishnam, that it would beadvantageous to design a component delivery system used in theprocessing of thin films on semiconductor substrates, and in particulara component delivery system which utilizes liquid precursors, whichwould reduce the temperature sensitivity of the respective components ineither the vapor or liquid state.

Another U.S. Pat. No. 6,179,277 by Huston of AMAT provides for improvedliquid vaporizer systems and methods for their use. Vaporizer systems ofthe invention are particularly useful for the vaporization of liquidshaving a relatively low vapor pressure, such astetrakisdiemthyl-amidotitanium (TDMAT). In one embodiment, a liquidvaporizer system includes a vaporizer unit having first and secondinlets and an outlet. The vaporizer system further includes a vesselhaving an inlet and an outlet, whereby the vessel inlet is operablyconnected to the vaporizer outlet. The vessel contains a plurality ofpassages which operably connect the vessel inlet and the vessel outlet.In this manner, liquids and/or gases flowing into the vaporizer unitthrough either or both of its two inlets, exit the vaporizer unit outletand enter

the vessel inlet. Liquids and/or gases pass through the plurality ofpassages and exit the vessel outlet. In this manner, heating vaporizerunit and vessel to desired temperatures results in the vaporization ofthe liquid, such as liquid TDMAT.

Another apparatus by AMAT, namely, a liquid phosphorous precursordelivery apparatus is described in U.S. Pat. No. 5,925,189 by Nguyen etal., where the invention recognizes that the build-up of residue in ametal alloy injection valve used to inject a liquid phosphorousprecursor compound is due to the nickel in the alloy affecting theliquid phosphorous precursor compound. The invention thus providescomponents manufactured of an alloy having a low nickel content,preferably less than 5% nickel, and more preferably less than 1%. In anadditional aspect of the invention, the alloy is provided with a higherchromium content, preferably at least 15% chromium, more preferably16-27%.

As these vaporizer, or, vaporization, systems are used for the importantfunction of depositing thin films on wafers, what is needed is a methodfor quickly assessing the quality of the vaporization process andassuring that full vaporization takes place in the system so that thinfilms of required properties are obtained, and scrapped wafers areavoided as a result.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a methodof self-calibrating a thin film vaporization system.

It is another object of the present invention to provide a method ofreal time monitoring the liquid vaporization process in a thin filmvaporization system.

It is still another object of the present invention to provide a methodof determining the relationship between the pressure rise of a thin filmdepositing chamber and the flow rate of a liquid precursor in a thinfilm vaporization system.

It is yet another object of the present invention to provide a method ofusing the relationship between the chamber pressure and the liquid flowrate to determine any malfunction in the operation of a thin filmvaporization system.

It is an overall object of the present invention to provide a method ofpreventing the scrapping of semiconductor substrates due to improperdeposition of thin films in a thin film vaporization system.

These objects are accomplished by providing a thin film vaporizationsystem comprising stored liquid precursors in tanks under pressureconnected to a deposition chamber via a manifold which in turn isconnected to pipe lines emanating from each tank and coupled to ownliquid flow meters (LFMs) and injection valves (IVs); activating a servomechanism to pump down said deposition chamber to achieve partial vacuumtherein; opening a downstream throttle valve (TV) for a carrier gas toflow through said manifold to commence self-calibration; a first timingto monitor a baseline self-calibrated pressure by a pre-determined TVopening which correlates with the specified baseline pressure in saiddeposition chamber; a second timing to allow for the stabilization ofcarrier gas after throttling said TV to a predetermined opening;selecting a liquid precursor and its own said respective pipe line withsaid own LFM and own IV connected to said deposition chamber via saidmanifold; setting said own IV to a pre-determined opening to start saidliquid precursor to flow; setting said TV opening to a normal liquidprecursor flow rate for film deposition; a third timing to allow forliquid precursor flow to stabilize; a fourth timing to allowvaporization of said liquid precursor in said deposition chamber;measuring final pressure in said deposition chamber; stopping the flowof said precursor fluid; and pumping down said deposition chamber tocontinue with said film deposition pending the result of said pressurerise.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vaporization system used in the deposition of thin films onwafers in a chamber, according to prior art.

FIG. 2 is a vaporization system used in the deposition of thin films onwafers in a chamber, according to the present invention.

FIG. 3 a is Table I showing measured values of selected parameters of avaporization system with fully open throttle valve (TV) between theprocess chamber and the pumping line, according to the presentinvention.

FIG. 3 b is a plot of the parameters of FIG. 3 a, according to thepresent invention.

FIG. 4 a is Table II showing measured values of selected parameters of avaporization system with “self-calibrated” TV opening, according to thepresent invention.

FIG. 4 b is a plot of the parameters of FIG. 4 a, according to thepresent invention.

FIG. 5 is Table III showing the various steps used in self-calibratingand testing of TEOS liquid precursor flow and vaporization, according tothe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, specifically to Figs. FIGS. 2-5, there isshown a method of preventing the scrapping of semiconductor substratesdue to improper deposition of thin films in a thin film vaporizationsystem. This is accomplished by providing a method of self-calibratingand testing the flow of liquid precursors in the vaporization systemprior to the start of the deposition process. The vaporization of theliquid precursor in the deposition chamber and the concomitant pressurechange in the chamber is correlated with the vaporization process asmonitored downstream. This correlation is then used as a real timemonitoring mechanism for self-calibrating and testing the flow of liquidprecursors through the vaporization system. That the pressure change dueto vaporization in the chamber is used as the key parameter, the thinfilm deposition is hence controlled by that parameter which directlydetermines the film deposition characteristics.

More specifically, FIG. 2 shows a thin film vaporization system with aserial liquid delivery arrangement connected to an AMAT TEOS-baseddeposition chamber (100). Wafer (110) to receive a thin film TEOSdeposition is shown schematically in chamber (100). Process gases and/orvapors, from common manifold (120), enter deposition chamber (100)through a distribution nozzle or showerhead (not shown) positioned overwafer (110) in the chamber. Chamber (100) is evacuated or maintained ata subatmospheric pressure, but in any event is maintained at a lowerpressure than the carrier gas and process gases and/or vapors so thatthe gases and vapors flow through manifold (120) in the direction ofchamber (100), which is located at the end of the manifold (120). Thechamber is pumped down by means of a servo mechanism evacuating thechamber via the pipe line (200) shown in the same FIG. 2.

Manifold (120) has several junctures at which fluids that are used inthe thin film deposition process are admitted. In the preferredarrangement shown in FIG. 2, there are three such junctures ((130 a),(130 b) and (130 c)) where a combination injection valve/vaporizer (IV)boxes are located. The IV is preferably a venturi tube which is commonlyused for atomizing liquids. The IV boxes are also connected toindividual pipe lines ((140 a), (140 b) and (140 c)) emanating from flowmeters ((150 a), (150 b) and (150 c)) which measure the flow rates ofliquid precursors that flow from their respective storage tanks ((160a), (160 b) and (160 c)). The liquid precursors are made to flow intheir respective pipe lines ((165 a), (165 b) and (165 c)) bypressurizing their tanks with an inert gas, such as helium, andpreferably under a pressure between about 20 to 30 pounds per squareinch (psi). Helium entry points into the tanks are shown by referencenumerals (170 a), (170 b) and (170 c) in FIG. 2. It will be understoodthat the resulting pressure differential through each tank will causethe respective liquid precursor to flow through a liquid flow meter(LFM) down the pipe line into the IV box where the fluid is vaporized asit exits the venturi tube into the manifold, and then proceeds into thedeposition chamber (100).

A source of carrier gas, such as argon, nitrogen, but preferably helium,is also connected to manifold (120) through a pipe line (180) with aflow controller (MFC). It will be noted that the carrier gas enters themanifold at a point farthest away or upstream of deposition chamber(100) so that the carrier gas entering manifold (120) passes through theentire length of the manifold prior to entering the deposition chamber,(100).

In the AMAT TEOS-based vaporization system used in the presentmanufacturing line, liquid precursors tetraethylorthosilicate (TEOS),triethylborate (TEB), and triethyLphosphate (TEPO) are employed todeposit borophosphosilicate Glass (BPSG) thin films on wafers. Otherprecursors are also used to form other types of thin films. However, ithas been the experience in the present manufacturing line that thequality of the liquid vaporization, that is, the amount of vaporizationand hence the amount of vapor mixed with liquid, after passing theinjector valves, or, IVs, and entering the deposition chamber is verycritical to the forming of thin films with the required properties. Eventhough liquid flow meters (LFMs) provide liquid flow rate readings,because they are upstream of the IVs, they are not capable of detectingany malfunction in the liquid vaporization process downstream within theIVs. In other words, even though the liquid flow rate may be adequate,that, by itself, is not a guarantee that the vapor quality downstreamthe LFM is adequate for proper film thickness and uniformity to beformed on wafers in the deposition chamber. This is because the liquidvaporization is affected by the conditions of the injection valve, i.e.,whether clogged or not, by liquid and valve temperatures, as it would beexpected. It will be noted in passing, though not shown, that heaterstrips are usually employed at various sections in the IV boxes andalong the manifold to control the liquid/vapor temperature. To a largeextent, none of these conditions will be reflected in the liquid flowrates measured by LFMs. Therefore, without a proper monitoring system ofthe vaporization process, the manufacturing line experiences manyunwanted wafer scraps.

It is a main feature and key aspect of the present invention to providea means for real-time monitoring of any malfunction in the vaporizationprocess during the deposition of thin films on wafers. The real-timemonitoring that is disclosed in the instant invention relies upon acorrelation between the pressure rise in the deposition chamber and thequality of the vaporization process, and hence, that of the quality ofthe thin film being deposited. Furthermore, the disclosed chamberpressure rise is independent of the chamber itself. Once the particularpressure level is achieved with any one of the AMAT chambers withincertain range, then all of the vaporization system is ready for properfilm deposition process.

These results are shown in FIGS. 3 a-3 b and FIGS. 4 a-4 b, with a majordifference between the two sets of Figures. FIG. 3 b is a plot of thevalues measured in FIG. 3 a, where the chamber pressure of two differentchambers A and B are measured at the same flow rate of TEOS liquidprecursor. The measurements of FIGS. 3 a and 3 b are made with thecarrier gas helium being throttled fully open and the carrier gas flowset at 800 standard cubic centimeter per minute (sccm). (It will benoted that the flow rate of the liquids is given in units of milligramper minute (mgm)). Under those conditions, the TEOS precursor flow rateand chamber pressure vary as shown in Table I and in the plot of FIG. 3a. It will be noted that with two different chambers A and B, the flowrate is multifunctional, that is, not unique. However, experiments show,as seen in FIGS. 4 a and 4 b that when the throttle valve is set at avalue called the “self-calibration” value, then the data points for thesame two chambers coalesce, that is, the chamber pressure rise becomesunique and independent of the chamber being used. At the same time, itis found that the vaporization process is acceptable to yield uniformthin film properties. Thus, it is disclosed that when the chamberpressure reaches greater than 7.0 torr, the system is properlyfunctional.

In the operation of a vaporization system, therefore, the system can bereadied, that is, calibrated and tested, for each liquid precursor,before depositing thin films according to Table III shown in FIG. 5. Itwill be noted in the first column on the left of Table III, that some ofthe parameters that are included there are not needed during theself-calibration and test mode of the system, although they are includedin the Table to indicate that they may be used during the actual thinfilm deposition. For example, neither radio frequency (RF) power, norend-point (EP) selection is used other than during the actual depositionmode. It will be known that end-point detection is usually determined byfluorine concentration detector in the chamber. However, the end-pointof each process step shown in FIG. 3 is predetermined by time stepcontrol as indicated in the third row of Table III, except for theimportant step 4 for vaporization. It is a key aspect of the presentinvention that the system is only acceptable for thin film depositiononly after the chamber pressure reaches 7 torr, and only within amaximum time step of 5 seconds from a baseline value.

It will be noted that the time required for chamber pressure to rise toa particular value in the film deposition chamber after the introductionof vaporized TEOS liquid precursor will be dependent upon the throttlevalve condition and the efficiency of the chamber pumping system.Different pumping system conditions will give rise to different durationfor chamber pressure to reach 7 torr. To normalize this condition, a“self-calibration” step is incorporated to the beginning of the testingprocedure where for a particular throttle valve setting and pumpingsystem, the chamber pressure is first allowed to reach 3.0 torr, as abaseline value. Subsequently, the success of the calibration process isjudged by the important 4^(th) step in FIG. 5. That is, whether or notthe TEOS liquid flow is fully vaporized to get the chamber pressure from3 torr to 7 torr in 5 seconds. If the vaporization is not 100% complete,the duration for the pressure rise will be less than 7 torr and longerthan 5 seconds, at which time the system will send a warning message toa monitor screen or to a host system for trouble shooting. Hence, it iscritical that at least an upperline of 7 torr in the chamber must bereached from a baseline of 3 torr within the times indicated in TableIII of FIG. 5.

More specifically, the procedure for self-calibrating and testing thevaporization system shown in FIG. 2 starts with step 1 of Table III inFIG. 5, namely with self-calibration after having chosen any one ofchambers A, B, C, D, . . . . It will be noted from the same Table thatthe heated fixture is spaced nominally at 290 mils from the distributionshowerhead, that is, between about 250 to 350 mils, and heated nominallyto 400° C. between about 350 to 450° C.; carrier gas helium is flowingnominally at 800 milligrams per minute (mgm) between about 700 to 900mgm; no end-point (EP) detection from the chamber is used, and no RFpower is turned on. In the first self-calibration mode, the chamberpressure is maintained at a nominal baseline pressure of 3 torr betweenabout 2 to 4 torr by a special TV servo step which controls the degreeof opening of the TV. The purpose for this step is to find out abaseline TV servo step which will be fixed from step 2 through step 4.This baseline TV servo step will then make chamber pressure riseindependent of chamber what chamber is used. The preferred nominal timeto reach the baseline pressure is 10 seconds between about 5 to 15seconds.

At the 2^(nd) step, the helium surge through the throttle valve (TV) isallowed to settle, or stabilize, within a nominal time of 5 secondsbetween about 4 to 6 seconds. Then at the 3^(rd) step, TEOS liquidprecursor injection valve is opened to allow a nominal flow of 900 mgmbetween about 800 to 1000 mgm. The settling, or stabilization time forthe TEOS liquid is nominally 8 seconds between about 7 to 9 seconds.

At the next key 4^(th) step, the TEOS liquid vaporization is verified.If 100% vaporization takes place, then the chamber pressure rises to anominal value of 7 torr between about 6.5 and 7.5 torr within a nominaltime period of 5 seconds between about 4 to 6 seconds. Providing thatthis step is successful, the flow of TEOS liquid is stopped and thechamber is pumped down within the time sequences shown in Table III ofFIG. 5 and the total vaporization system is readied for the actual filmdeposition.

If, on the other hand, the 4^(th) step is not successful, then thesystem will send a warning message to a monitor screen or to a hostsystem for trouble shooting.

Though these numerous details of the disclosed method are set forthhere, such as process parameters, to provide an understanding of thepresent invention, it will be obvious, however, to those skilled in theart that these specific details need not be employed to practice thepresent invention. At the same time, it will be evident that the samemethods may be employed in other similar process steps that are too manyto cite, such as, for example, using the self-calibration and testprocedure for other liquid precursors including, but not limited totrimethylphosphite (TMP), triethylphosphite (TEP), or triethylphosphate(TEPO); and/or a liquid boron source precursor such as, for example,trimethylborate (TMB) or triethylborate (TEB).

That is, while the invention has been particularly shown and describedwith reference to the preferred embodiments thereof, it will beunderstood by those skilled in the art that various changes in form anddetails may be made without departing from the spirit and scope of theinvention.

1. A method of self-calibrating and testing the vaporized flow of aliquid precursor in a thin film vaporization system comprising the stepsof: providing a thin film vaporization system comprising stored liquidprecursors in tanks under pressure connected to a deposition chamber viaa manifold which in turn is connected to pipe lines emanating from eachtank and coupled to own liquid flow meters (LFMs) and injection valves(IVs); activating a servo mechanism to pump down said deposition chamberto achieve partial vacuum therein; opening a downstream throttle valve(TV) for a carrier gas to flow through said manifold to commenceself-calibration wherein said carrier gas is a helium carrier gas; afirst timing to monitor a baseline self-calibrated pressure by apre-determined TV opening which correlates with the specified baselinepressure in said deposition chamber; a second timing to allow for thestabilization of carrier gas after throttling said TV to a predeterminedopening; selecting a liquid precursor and its own said respective pipeline with said own LFM and own IV connected to said deposition chambervia said manifold; setting said own IV to a predetermined opening tostart said liquid precursor to flow; setting said TV opening to a normalliquid precursor flow rate for film deposition; a third timing to allowfor liquid precursor flow to stabilize; a fourth timing to allowvaporization of said liquid precursor in said deposition chamber;measuring final pressure in said deposition chamber; stopping the flowof said precursor fluid; and pumping down said deposition chamber tocontinue with said film deposition pending the result of said pressurerise.
 2. The method according to claim 1, wherein said tanks arepressurized by helium gas.
 3. The method according to claim 2, whereinsaid helium gas is pressurized to between about 20 to 30 pounds persquare inch gauge (psig).
 4. The method according to claim 1, whereinsaid helium gas is kept at room temperature.
 5. The method according toclaim 1, wherein said manifold has heater elements.
 6. The methodaccording to claim 5, wherein said heated fixture elements are spacednominally at 290 mils between about 250 to 350 mils from distributionshower head.
 7. The method according to claim 5, wherein said heatedfixture is heated nominally to 400° C. between about 350 to 450° C. 8.The method according to claim 1, wherein flow of said helium carrier gasthrough said manifold is between about 750 to 850 milligrams per minute(mgm).
 9. The method according to claim 1, wherein said first timing isbetween about 5 to 15 seconds.
 10. The method according to claim 1,wherein said baseline self-calibrated pressure is between about 2 to 4torr.
 11. The method according to claim 1, wherein said second timing isbetween about 4 to 6 seconds.
 12. The method according to claim 1,wherein said liquid precursor is tetraethylorthosilicate (TEOS).
 13. Themethod according to claim 1, wherein said liquid precursor istriethylborate (TEB).
 14. The method according to claim 1, wherein saidliquid precursor is tri-ethylphosphate (TEPO).
 15. The method accordingto claim 1, wherein said injection valve (IV) comprises a venturi tube.16. The method according to claim 1, wherein said normal liquidprecursor flow rate is between about 800 to 1000 milligram per minute(mgm).
 17. The method according to claim 1, wherein said third timing toallow for liquid precursor to stabilize is between about 7 to 9 seconds.18. The method according to claim 1, wherein said fourth timing to allowfor liquid precursor vaporized flow to be verified is between about 4 to6 seconds.
 19. The method according to claim 1, wherein said finalpressure in said deposition chamber is between about 6.5 and 7.5 torr.20. The method according to claim 1, wherein said pumping down saiddeposition chamber is accomplished within between about 9 to 11 seconds.